Conventionally, LP gas is categorized into gas imported from industrial gas producing countries, and gas domestically generated as a secondary product when petrochemical products are produced. Import stations that store the LP gas transported by tankers from the industrial gas producing countries and oil refinery stations are called primary terminals. The LP gas in the primary terminals is loaded into coastal vessels and tank trucks, and shipped to secondary terminals, which are transit stations located along or away from the coasts. Further, the LP gas carried to the secondary terminals is transported to LP gas filling stations in various places, and is employed to fill gas cylinders in the filling stations.
The gas cylinders filled with the LP gas in the filling stations are delivered by deliverymen to customers' homes, such as general homes, apartment buildings and offices. The empty gas cylinders at the customers' houses are replaced with filled gas cylinders, and the empty gas cylinders are collected at the filling stations. The individual filling stations have fixed delivery areas to be assigned for deliverymen. Delivery slips for two to ten days, indicating the houses of customers in the delivery areas to deliver the gas cylinders, are handed over to the deliverymen.
The delivery slip is prepared by a delivery manager. First, for each customer, the remaining amount of the LP gas in the gas cylinder is predicted based on the gas usage history, the indication of a gas meter (hereinafter “meter indication”) installed at the customer's home, a delivery history, etc., and the next delivery due date for a gas cylinder is determined. The remaining amounts of the LP gas in the gas cylinders, thus predicted for all of the customers in the delivery areas allocated to the deliverymen, are added together to determine the amount of delivery of gas cylinders for two to ten days.
When the deliveryman has exchanged the gas cylinders in accordance with the delivery slip, he or she enters, to the delivery slip, the date of replacement, the meter indication on the date of replacement, the cylinder number and the individual safety inspection items. At the end of the daily delivery operation, the delivery slip is submitted to the delivery manager. The delivery manager examines the delivery slip thus returned to the delivery manager to determine whether there are omissions in entry, and thereafter, stores the slip as data used to calculate the next delivery due date. For such a system, various methods for increasing the efficiency for delivery of gas cylinders have been proposed (see patent literature 1).
Further, an idea that employs a handy terminal to simplify the delivery operation has also been also proposed. A delivery slip is stored in the handy terminal, and is interconnected to a service system provided for the delivery manger, so that calculation for the remaining amounts of gas in the gas cylinders, the calculation of the next delivery due date and the collection of the meter indication described above can be efficiently performed.
Recently, the filling operation performed at the individual filling stations is performed collectively at the secondary terminal, which therefore serves as a base for deliverymen, or the secondary terminal is not established for reduction of the distribution cost. However, for companies in charge of delivery of the LP gas, the total cost of distribution from the primary terminal to the customers can not yet be reduced.
Moreover, a handy terminal is an expensive device, and there is a risk that, if the handy terminal is misplaced, a large amount of customer data would be lost. Furthermore, the handy terminal must be carried back to the filling station where the delivery manger stays, and be connected to the service system to update data, and real-time use of information is not satisfactory.